Poultry carcasses have heretofore sometimes been skinned by hand to remove the fatty skin layer so that only the leaner flesh remains. However, to our knowledge no mechanical systems have heretofore been invented to remove the skin mechanically in a manner that is compatible with line speeds typically found in modern poultry processing plants.
The present invention contemplates first completely removing the wings from the carcass so that the trunk and both legs are left on the carcass. Either before or after the wing removal, the tail is also removed, leaving a small patch of exposed flesh at the posterior end of the carcass. The exposed patch at the posterior of the carcass facilitates the insertion of an air nozzle that slips under the skin just above the meat so that a stream of high pressure air from the nozzle may force the skin away from the meat as the skin tends to be inflated by the nozzle. As the nozzle is moved along the backbone under the skin, a knife associated with the nozzle slits the skin all along the backbone, whereupon the carcass is turned end-for-end and is presented to a second stationary nozzle along the conveyor line which is inserted under the breast skin of the carcass. As the second nozzle continues to be forced under the skin along the breast bone, a second air stream tends to once again inflate and pull the skin away from the meat, while another knife associated with the second nozzle slits the breast skin along the full length of the breast so that, by this time, two complete half sheets of skin are presented. Thereupon, the carcass is presented to stationary peeling rods which are disposed in parallel alignment with the path of travel of the conveyor and slip under the two halves of skin in such a manner as to force them to pull away from the sides of the carcass generally down toward the legs such that the trunk of the carcass is wholly peeled free of skin down to the legs. At that point, the skin may be grasped manually or by suitable mechanical means and pulled down and over the legs to leave the carcass entirely skin-free.
The carcasses are mounted on special mandrels which preferably take the form of those disclosed in Canadian patent application 2,014,081 filed Apr. 6, 1990, titled "Poultry Processing Apparatus and Method" and filed in the names of Rudolph J. Tieleman, et al. Such mandrels comprise elongated, tapering bodies that stand in an upright condition during a portion of their travel along a predetermined conveying line so that the carcasses may be manually loaded onto the mandrels as the mandrels are inserted up into the body cavities of the carcasses. Stationary cam mechanisms along the path of travel of the mandrels interact with operating mechanisms to maintain the mandrels in upright positions during part of their movement along the path of travel, rotate them into reclining positions with the posterior ends leading during another part of the path of travel, and rotate them into prone positions with the anterior ends leading during other portions of the path of travel. After each carcass has first been placed on one of the mandrels in an upright position, the carcass passes through a wing cutting station in which both wings are completely severed from the carcass. Inwardly inclined cutting discs situated on opposite sides of the path of travel of the carcass start severance of the wings at one certain angular position but are swung slightly outwardly away from the path of travel as the carcass continues to move and severance progresses so that the angle cutters will not slice deeply into the breast of the carcass.
After passing through the wing cutting station, each mandrel is cammed into its reclining position to present the carcass posterior end first and back up to a back skin slitting station which loosens the skin along the backbone of the carcass and makes a complete slit from the tail area of the carcass up to the neck region along the backbone. A plurality of air streams are directed under the back skin at this station to facilitate the loosening and slitting process, including one or more streams issuing from a generally flat, pointed, stationary nozzle that is centered in the path of travel of the carcass in such a manner as to slip under the back skin directly above the tail region and along the backbone. A rotary drive wheel which directly overlies the flat nozzle near its tip engages the outside of the back skin as the nozzle enters the skin so as to force the skin to climb up onto the nozzle and thereby assure proper penetration of the nozzle tip under the skin and along the backbone. As the skin climbs up onto the nozzle and the nozzle moves along the backbone, a centrally positioned knife blade slits the skin to facilitate its subsequent removal from the carcass.
Upon leaving the back skin slitting station the mandrel on which the carcass is impaled is cammed 180.degree. into a prone position with the breast up and the anterior end of the carcass leading. In that orientation the carcass moves through a breast skin slitting station in which a second nozzle, similar to that used at the back skin slitting station, slips under the breast skin near the neck portion of the carcass as streams of air are directed under the breast skin to loosen and inflate the skin to facilitate entry of the nozzle. A second rotary drive wheel immediately overlying the breast nozzle adjacent its tip end serves to drive the breast skin up onto the nozzle in a manner similar to that which occurred with the back skin. Continued advancement of the carcass in the breast up position causes the nozzle to be moved relatively along the breast bone from the neck end to the tail region of the carcass, producing a continuous slit from a knife blade associated with the breast nozzle.
After passage through the breast skin slitting station the mandrel carrying the carcass is cammed 90.degree. into an upright position with the neck region of the carcass facing upwardly and the tail region facing downwardly. As the carcass moves through the peeling station in this position, air is directed at the two halves of skin on opposite sides of the carcass to help billow out the skin and facilitate entry of two separate, individual peeling rods located on opposite sides of the path of travel in horizontal attitudes. The two rods converge at their upstream ends to be spaced apart a distance corresponding to the width of the carcass so that the leading tips of the rods slip under the skin halves at approximately their vertical midpoints. Continued advancement of the carcass coupled with diverging orientation of the rods causes the skin halves to be progressively peeled from the carcass adjacent the upper and lower areas of connection until the two opposite skin halves are totally disconnected from the meat down to an area immediately adjacent the legs. At that point an operator may manually grip the skin halves and pull them downwardly off the carcass to complete the total skinning process or they may be removed by suitable mechanical means, whereupon the skinned carcass may be removed from the machine.